U.S. Sen. John McCain rebukes President Donald Trump in a new memoir, accusing his fellow Republican of failing to uphold U.S. values by showering praise on international "tyrants," discrediting the media, ignoring human rights and demeaning refugees.

"Flattery secures his friendship, criticism his enmity," wrote McCain in "The Restless Wave," which he co-authored with longtime aide Mark Salter.

"It is hard to know what to expect from President Trump, what's a pose, what's legitimate," McCain said in the book that is due to be released on May 22. An advance copy was sent to Reuters by publisher Simon & Schuster.